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RogerC

Review of Maha MH-C9000 Wizard NiMH Battery charger

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photos of charger at:

http://www.rogercarlsonphotography.com/gal...ment/maha_9000/

 

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I've long been a fan of Maha batteries and chargers. Maha is one of several brands that seem to push the limits of battery capacity every year and stay at the front of the pack. I've bought a few sets of the latest Mahas before every major vacation, so I've accumulated pretty much the full collection of Maha battery capacities.

 

Maha also seems to stay on top of battery charger technology as well, releasing new chargers every year or so.

 

I recent picked up the new Maha MH-C9000 Wizard charger ($74 from Thomas Distributing). This is my third Maha charger.

 

My first was the MH-C401FS, which I really liked. It charges 4 batteries independently and has a slow or fast charge setting. Fast is great on the road, when you need batteries fresh for every dive, but slow is fine at home, when you're not in a hurry, since batteries kept cool have a longer life. The 401 charges at 1000mA in fast mode, and only 300mA in slow mode.

 

My second charger was the MH-C204W. It came highly recommended by Dave Etchells, who runs a battery test page at http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM. I ended up not liking it; it only charges fast, which isn't necessary at home, and it only charges batteries in pairs. When you have a single cell fail in an older set, it's not immediately obvious which cell has failed in each pair. I also worry that in paired charging, neither cell gets the optimal charge that it would really like. And it ran pretty hot, charging at 2000mA, which I thought was too fast, particularly at home, when speed isn't an issue the way it is on a dive trip.

 

MH-C401FS:

http://www.mahaenergy.com/store/viewItem.asp?idProduct=178

MH-C204W:

http://www.mahaenergy.com/store/viewItem.asp?idProduct=352

Maha MH-C9000:

http://www.mahaenergy.com/store/viewitem.asp?idproduct=423

 

I ended up selling the 204 and hanging onto the older 401. I actually thought that the 401 might be my last charger, as I've been hoping to get into an SLR camera and out of my compact camera, which would put me out of the AA NiMH business. I finally came to the conclusion that I'm not likely to ever stop using AA NiMH's entirely; they'll always be used in some strobes and in various electronics around the house, in some flashlights, and in my Athena Ring Strobe.

 

I also came to the conclusion that my venerable 401 charger might not be up to the task of charging the new higher capacity batteries. It is possible to charge a battery too slowly; batteries should ideally be charged at a rate that fully charges them in no faster than 1 hour, or no slower than 2 hours. This is referred to as 1C or 0.5C, where C stands for "Capacity". In other words, a 2600 mAh battery should be charged at a rate of 0.5C, or 1300 mA, or up to 1C, or 2600mA. These rates would charge the battery fully in 2 hours or 1 hour, respectively. The 401 was running at only 1000mA in fast mode, and only 300mA in slow mode. Not strong enough, perhaps.

 

Anyway, I had begun to see some odd behavior in my newest batteries. Some sets weren't holding up as long as older sets. I initially wondered if batteries with such high capacity just plain had shorter lives; maybe 2600mAh batteries only last a year, while 2400mAh batteries can go for several years. But I began to wonder if it was not the batteries, but the charger. Maybe the low power of the old 401 charger was just not putting out enough juice to keep the chemistry in these new batteries working well.

 

I also began to wonder what the capacity was in my very oldest batteries, batteries which had been relegated to devices around the house and would go on no further dive trips.

 

And on one recent dive trip, I found myself wishing for a charger with a status display, to tell me if a set of batteries is near a complete charge and is ready to go diving, or if they need to stay on longer.

 

And so I ordered the 9000 charger from Thomas Distributing, with a few sets of the latest Maha AA's, 2700mAh capacity. Technology advances rapidly; I think the wizard charger was the same price as the old 401 originally was (401 price including the optional external international power supply, which is built into the 9000).

 

Maha chargers have had the same form factor for many years. The Wizard is a new form factor, about 2 or 3 times the size of the 401, see the photo below. It has a large screen, cooling vents, and wide spacing on the batteries , for cooling during charging. It is heavier, at 16 ounces vs 8 for the 401 (weight for both includes international wall wart power supply. The 50/60Hz 110V/220V power supply is included with the 9000, optional with the 401.

 

The 9000 has 5 modes:

 

- Charge. Recommended for batteries used frequently. This is the default mode, with a default rate of 1000mA. Rates are selectable from 200mA to 2000mA.

 

- Refresh/Analyze. Recommended for batteries that have been in storage for 2 weeks to 3 months, or batteries showing signs of capacity loss.This mode charges the battery, rests, fully discharges the batteries, rests, then recharges, all at programmable rates.

 

- Break-in. Recommended for new batteries, those that have been unused for 60 days or more, or those showing more serious capacity problems. Applies a 16 hour .1C charge, rests 1 hour, 8 hour .2C discharge, rest 1 hour, 16 hour 0.1C charge.

 

- Discharge. Simply discharges the battery at a selected rate. Not sure why you'd do this, I guess it's for battery geeks doing tests.

 

- Cycle. Performs a charge/discharge cycle at the programmed rates, for the programmed number of times.

 

The charger comes with a wall-brick power supply. It has 2 US prongs, but can run off 50-60Hz and 110VAC or 220VAC. The charger's status displays show the rate the battery the charger is charging at, how much total charge the battery has gotten, and how long the cycle has taken. At the end of a charge cycle, the charger reports the total charge the battery has accumulated, which will show the battery's capacity (if the battery was fully discharged during use or during the charge cycle).

 

I put the charger to work right away, running a break-in on my new batteries and oldest batteries, and running a refresh cycle on all my sets. With about 12 sets of batteries, the process took almost 2 weeks. Some of the cycles can be quite slow. If you find yourself doing a lot of cycling and refreshing with your batteries, or if you are supplying power to two cameras, or if you want to have batteries ready to go all the time, even while you tinker with another set, you might want to consider two chargers.

 

There are several things I really like about the charger.

 

What I like most about it is the display. It's great to really know how close to done a charging cycle is, and it's great to know for certain what the health of a set of batteries is. It's great to know for certain that one cell has really fallen behind the other 3 in capacity, or to know that a full set has fallen to almost nothing. Most of my sets, even the very oldest ones, were still pretty healthy, but all my 2200mAh sets had dropped to about half their capacity, and went into the bin for proper disposal. Maybe the 2200's just had poor chemistry compared to the 2000's or 2400's.

 

I also really like the the speed of the charger. I charge at 0.5C, so my batteries would be ready to go in only two hours if fully discharged; at this rate, they are ready to go pretty quickly and they don't get very warm during the charge.

 

Finally, I just like having the latest, smartest charger for my cells. It's nothing quantitative, but I like to think the charger has a better brain and incorporates a smarter charging profile than the the 401's.

 

What I dislike about it is obviously the size and weight. Every ounce counts for the traveling photographer, particularly the underwater photographer.

 

What I also dislike about it is the default mode: if you simple put in a set of batteries and walk away, the charger defaults to a rate of 1000mA. This is less than the recommended 0.5C minimum rate for the newest 2700mAh batteries, which want a minimum rate of 1400mA. It would be nice if the default rate could be set and stored somehow. It would be most ideal if the charger would remember the setting last used in every mode.

 

All in all, I'm very happy with the charger, and it will be going on trips with me, it's worth the size and weight. I'll probably also keep one of my old 401 chargers, and bring it along just for backup; I hate to be dependent on any single piece of electronics when traveling to areas with spiky power grids.

Edited by RogerC

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Great review Roger, thanks. I use their 8-cell charger and like it a lot. That way I can charge 2 strobes worth at a time from one compact unit. I can't remember the model number of the unit I have though...

 

Cheers

James

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I'll second that maha 8 cell charger. Also thumbs up on their powerex brand 2700mAh rechargeable AA's which seem to be working as well as the Sanyo branded ones.

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I'll "third" that 8 cell Maha charger...as soon as you put the batteries in, you get a "status" on how depleted they are and it's really, really fast charging the 2700 mAh batteries...love it! And it's not very heavy either, thankfully!

 

You can put as few as one battery (or any number) in at a time if you'd like, also, so if you're trying to get a read on the performace of older NiMH batteries, it will show you their status while they're charging....

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Actually, the 8 cell charger IS quite heavy compared to two 204 chargers. You have to add the size and weight of the power supply and the two together weigh 20 oz. A 204 charger weighs 4 oz so you can carry 5 of those at the same travel weight! Two or more 4 cell chargers also provide redundancy. I used the 8 cell charger on the last trip but I don't think I'll continue because of the weight. The 8 cell charger is a perfectly good solution but there is lighter. I can travel with a complete, redundant charging solution for less that the weight of the 8 cell power supply alone.

 

I don't agree that a battery should be optimally charged using at least 0.5C. The slower a battery is charged, the better. 0.1C works great but we usually can't afford to wait that long on dive trips.

 

I don't like that 204 chargers only charge in pairs, but over the course of a trip (even a very long one) it's unlikely to make a difference. AA batteries are cheap, too. It's totally reasonable to have a reconditioning charger at home and use a less capable charger on a trip and it's also affordable to replace batteries frequently. The question is whether the more compact but less capable 204 is better than the 401 with its wall wart.

 

What's most important is that a charger do a good job at filling batteries each time. Single cell chargers and slower charge rates are more likely to accomplish this. It's also important that the charger be robust in the presence of crappy wall current. I've had great success with Maha but have been really hosed by other manufacturers.

 

I tried a set of PowerEx 2700s along with Sanyo 2700s on my last trip. The Sanyos self-discharged faster but they provided noticably more strobe cycles. It may have been just a poor sample size, but I'd personally buy the Sanyos.

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